Endemic Dragonflies of Late Pleistocene
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Odonatologica 4(1): 1-9 March I, 1975 Endemic dragonflies of Late Pleistocene age of the Hula Lake area (northern Israel), with notes on the Calopterygidae of the rivers Jordan (Israel, Jordan) and Litani (The Lebanon), and description of Urothemis edwardsi hulae subspec. nov. (Libellulidae)* H.J. Dumont Institute of Zoology, University of Ghent, Ledeganckstraat 35, B-9000 Ghent, Belgium Received January 7, 1975 Volcanic events during the middle Pleistocene blocked the Jordan Rift at the frontier between Israel and the Lebanon. South of it, in the Hula Lake and area, four endemic subspecies of dragonflies evolved, presumably during after the Wiirm. They are all subspecies to Ethiopian species. North of the barrier evolved Calopteryx hyalina Martin, a taxon of uncertain status. The two endemic Anisoptera of Lake Hula (Rhyothemis semihyalinasyriaca Selys and extinct while Urothemis edwardsi hulae ssp.n.) are probably now, the Zygoptera ( Pseudagrion torridum hulae Dumont and P. sublacteum mortoni Ris & Schmidt) are still in existence. INTRODUCTION The dragonfly fauna of the Mediterranean coast of the Near East is quite of of complex. In terms present-day zoogeographical divisions, it consists a of majority Mediterranean elements, with an immixture of Ethiopian and Oriental species. In addition, a number of endemics occur. It is the nature of forms some among these endemics that the object of this paper. * Paper presented at the Fourth Colloquium of Dutch and Belgian Dragonfly Workers, Utrecht, December 14, 1974, 1 THE ENDEMICS OF THE UPPER JORDAN VALLEY (LAKE HULA AREA) PSEUDAGRION TORRIDUM HULAE DUMONT, 1974 Restricted to Lake Hula where it is common. Described and figured in DUMONT, 1974. Structurally, it is almost identical to P. t. torridum Selys. This is widely distributed in Africa, reaching Egypt and the South-Western edge of the Sinai desert, which is the North-Eastern limit ofits known distribution.The present-time disjunction of the Hula population is thus about 700 km. E.C.G. Fig. 1 (a) Hind wing of Rhyothemis s. semihyalina, <5, Maun, Botswana (leg. Pinhey); - (b) Hind wing of R. semihyalinasyriaca, 9, Selys’ type from ’’Syria”. 2 PSEUDAGRION SUBLACTEUM MORTONI (RIS & SCHMIDT, 1936) in Occurring on Lake Hula but also other places of the Jordan valley (see map in DUMONT, 1974). Present disjunction with the Ethiopian stock unknown, since P. s. sublacteum(Karsch) might occur in Egypt. RHYOTHEMIS SEMIHYALINA SYRIACA SELYS, 1850 Figures 1 b; 2 a, b female Described by Selys on a in the Latreille collection, labeled ’’Syria” without any further indication. According to the description, it differs from typical semihyalina in having the black spot at the base of the hindwings more reduced, leaving a narrow hyaline fringe along the posterior border of the wing. I found and these characters well exemplified on the type (Brussels Museum) on the following additional material: 266, Department of Genetics, The Hebrew University of Jerusalem, one without label, one labeled Hula, 23.VI.1952; 10 specimens in the Department of Zoology, University of Tel Aviv (7 from Hula, of one from Daphne north Hula, two without label); finally, a couple in my private collection, both from Hulata, 1.V1I1.1947 and 23-28.V1.1950. These, together with a male in the collection of Kibbutz Beit Ussishkin (Israel), taken at Hula on 10.VI.1954, a series in the collection of Kibbutz Beit Gordon (Israel), taken at Tiberias, 28.V.1931, 17.V.1939, 3.V.1946, East of Bet-Yarah, 16.VI.1942 and Hula, 8.VI.1944, the male and females recorded by MORTON (1924) from Hula, 24.V.1922 and the male recorded by SCHMIDT (1938) from 2 of - Fig. (a) Accessory genitalia Rhyothemis semihyalina syriaca, <5, lateral view; (b) ultimate abdominal of of the segments a female same, showing the valvules. 3 Ferum near Rosh Pina, Hula Lake, 25.VII.1928, are the only existing specimens that I know of, in all about thirty at the most. I might add that the hyaline fringe in the hindwing is wider in females than in males, and that the base of the hindwing is less widened in R. semihyalina syriaca than in R. semihyalina semihyalina (Fig. la, b). Selys’ ’’Syrian” specimens might well have come from the Lake Hula area, since all other known specimens were collected here. Structurally, the subspecies is identical with the - Fig. 3 Urothemis edwardsi hulae subsp.n.: (a) Abdominal colour pattern of the male; (b) the Accessory genitalia of male, lateral view; — (c) Appendices of the male, lateral view; — (d) Ultimate abdominal segments ofa female, showing the valvules. 4 nomino-typical one in both sexes (Fig. 2a, b). The disjunction is considerable; typical semihyalina occurs in Algeria (SELYS, 1849) and further in the whole Ethiopian region (PINHEY, 1962). UROTHEMIS EDWARDSI HULAE SSP. NOV. Figures 3 a-d, 4 a Material. - Holotype: a fully adult, pruinose d, labeled Huleh (Hula), 9.VI. 1952, deposited at the Department of Zoology, University of Tel Aviv. Paratypeseries: 7dd, Hula, 23.VI.1952, 699, Hula, 23.VI.1952, Department of Genetics, The Hebrew Uni- versity of Jerusalem; Id, 19, same label, author’s collection; Id, 19, same labels, British Museum (Natural History); Id, Hula, 4.XI.1946, author’s collection; 19, Jericho, 16.VII.1942 (leg. Bytinski-Salz), 399, Hulata, 1.VIII.1947 (leg. Bytinski-Salz), 2 66, Hula, 9.VI.1952 and 19, Ulmania (Hulavalley), 2.VII.1947, all at the Department of Zoology, Tel Aviv University. Fig. 4 (a) Hind wing of Urothemis edwardsi hulae subsp.n.; - (b) Hind wing of U. e. edwardsi, Maun, Botswana (E.C.G. Pinhey leg.). 5 Additional material. - 19, Gonen, 5.VI.19S3, coll. Kibbutz Beit Ussishkin; a series in both sexes, coll. Kibbutz Beit-Gordon, from Dan, 1.V1I.1953, Gonen, 5.VI.1953, and Sede Nehemya, without date. Further, a female was reported by Morton (1924) from Hula, 24.V.1922 and 4 66, 499 from Rosh Pina-Hula lake (”an Wassergraben”), 23.VII.1928, by SCHMIDT (1938). Male: structurally identical with U. e. edwardsi (Selys). Hamuli and appendices as in Figures 3b, c. Differs from nominal subspecies in the extent of the basal spot on the hindwings which is greatly reduced (Fig. 4a). of Female: structurally identical to U. e. edwardsi (Selys). Structure val- reduced male. vules as in Figure 3d. The basal spot on the hindwings as in the Distribution: all female specimens, save a single taken near Jericho, were captured at lake Hula and surroundings. The nominal subspecies, although described from Algeria (SELYS, 1849), is widely distributed in tropical Africa (P1NHEY, 1962). DISCUSSION One rarely has the privilege to deal with the fauna of a lake that has been famous since antiquity. As stated by COWGILL (1969), a first rough estimate of its superficy was given by Flavius Josephus, somewhere between 69 and 79 A.D. Throughout history, stray notes on the lake were published by visitors to the it holy land, some claiming that might completely dry up during summer, others of and that surround it. giving descriptions its shape, depth, the papyrus swamps It is the first lake on the course of the River Jordan, and therefore, the parts of of it directly adjacent to the channel the river can never have been completely much dry. The second and major lake, Lake Tiberias (Yam Kinneret) has a poorer dragonfly fauna than Hula, as have many large and deep lakes. The events of interest to this paper took place, presumably some 35-30,000 of the Rift north of the Hula rather years ago, and are the damming Jordan by of the basins of complicated volcanic activities, finally resulting in a separation and transformationof the Jordan and the Litani Rivers, the a previously existing swamp into the Hula lake. While this process was taking place, the Wiirm glaci- ation was in evidence in Europe and a corresponding pluvial existed in North Africa and Egypt. Although the synchronism of Pleistocene glaciations and pluvials is not rigorous (there have been more pluvials than glaciations), they shown for were nicely simultaneous during the Wiirm, as BUTZER (1971) has Libya and Egypt. For Israel, PICARD (1963) arrives at the conclusion that no appreciable climatic changes occurred during the late Pleistocene, although DAN (1961) gives pedological evidence that the basaltic soils of the upper Jordan valley are typical of a climate with a precipitation of about twice the present. This leads to the suggestion that the Arava valley and the Sinai were more humid than Some to-day and were no barrier to non-migrant dragonflies. Ethiopian 6 that had followed the species Nile-pathway could thus cross the Sinai and Negev deserts and reach the Jordan where valley, they moved North up to Hula, but apparently did not cross the Yarda basalt between the Naphtali mountains (of Cretaceous age) and the Hermon (of Jurassic age). The cessation of this humid occurred period in an oscillatory way (BUTZER, 1971), and may have become efficient around 15000 BP. It resulted in a progressive shrinking of the number of viable for in the South but also the biotopes dragonflies, not only in present Syrian desert. This is proven by the distribution of e.g. Brachythemis fuscopal- liata which lives (Selys), now in the great marshes of Iraq, but has left relict populations in the Adana peninsula (S. Turkey) and at Hula (DUMONT, 1972). the habitats suitable for the reduced the Likewise, Ethiopian immigrants were to upper Jordan valley, roughly the Hula lake and its surrounding marshes. The for arguments placing these Ethiopian immigrants in the Wiirm(and not at an earlier date) follow from: (1) their absence North of the Jordan valley. The objection might be raised that we do not know enough about the fauna of The Lebanon and Western Syria to make such a statement acceptable.